This invention relates to an apparatus for attaching bar codes to reticle cases which contain therein reticles (original integrated circuit patterns) in order to control or inventory the reticles to be used in the process of manufacturing semiconductors.
Conventional reticles have printed or marked code numbers of integrated circuits to be manufactured, on their corners in an individual character size of 0.5-2 mm. After having done with them, the reticles are stored for control by means of the code numbers. Each reticle is stored in a flat and square reticle case 2, as shown in FIG. 1, of synthetic resin make having a transparent upper surface 1. The body part 3 of the reticle case 2 is covered with a lid 4 of sliding type whose upper surface 1 is transparent. Normally, the body part 3 and the lid 4 are engaged with each other via a lock mechanism (not shown) by a long lock 5 on a side thereof. The body part 3 is taken out, by sliding, through an outlet 6 of the lid 4 by rotating the lock 5 to release the lock mechanism, and a reticle 7 inside the body part 3 is taken out. The patterned surface of the reticle 7 is covered with a protection cover (pelicle) 8. A 10-digit code number 9 is marked on the reticle 7 outside the protection cover 8 in alignment with the takeout direction in a character height of 1 mm.
Another type of reticle case is shown in FIG. 2. In this type, a side plate 10, which can be swung upwards to open, is provided in a body part 3 of square case shape whose upper surface 1 is transparent. The reticle 7 is taken in (or inserted into), or taken out through, the outlet 6 by opening the side plate 10. A protection cover 8 is also attached to the reticle 7. A code number 9 comprising small 10-digit code numerals is printed on the reticle 7 outside the protection cover 8 in a direction at right angles to the takeout direction.
In case where a large number of reticles are stored, it is not easy to find out a reticle case containing therein a required reticle. It is not easy to recognize the code number with naked eyes through the transparent upper surface because the code number is small.
If the same code number as that on the reticle to be stored therein is marked large also on the reticle case, it will be easy to find it out. However, when the code number comprises characters or numerals extending as long as 30 digits, manually marking them on the reticle case will take much time and is not preferable in that a risk of making a mistake in marking is accompanied. It is also considered to print the characters or numerals on a label with a printing machine and then attach the label to the reticle case. It is also not preferable to do so because there is a risk of wrongly reading the code number on the reticle case because it is small, and because there is a risk of wrongly operating the printing machine.
Upon careful study, the inventors have come to a conclusion that this kind of risks can be solved by optically reading the characters or marks on the reticle, printing a mark comprising a bar code on a label based on data obtained by the optical reading, and then attaching the label to the reticle case. If a bar code is attached, a reticle case containing a desired reticle can be easily found out by reading the bar code with a bar code reader.